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Chapter 4
Functional
Anatomy of
Prokaryotic and
Eukaryotic Cells
Copyright © 2010 Pearson Education, Inc.
Lectures prepared by Christine L. Case
Q&A
 Penicillin was called
a “miracle drug”
because it doesn’t
harm human cells.
Why doesn’t it?

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Look for the answer in the chapter.
Prokaryotic and Eukaryotic Cells
Learning Objective
4-1 Compare and contrast the overall cell structure of
prokaryotes and eukaryotes.
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Prokaryotic and Eukaryotic Cells
 Prokaryote comes from the Greek words for
prenucleus.
 Eukaryote comes from the Greek words for
true nucleus.
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Prokaryote
Eukaryote
 One circular
chromosome, not in a
membrane
 No histones
 No organelles
 Peptidoglycan cell walls
if Bacteria
 Pseudomurein cell walls
if Archaea
 Binary fission
 Paired chromosomes,
in nuclear membrane
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 Histones
 Organelles
 Polysaccharide cell
walls
 Mitotic spindle
Check Your Understanding
Check Your Understanding
 What is the main feature that distinguishes
prokaryotes from eukaryotes? 4-1
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The Prokaryotic Cell
Learning Objective
4-2 Identify the three basic shapes of bacteria.
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Prokaryotic Cells: Shapes
 Average size: 0.2 –1.0 µm  2 – 8 µm
 Most bacteria are monomorphic
 A few are pleomorphic
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Figure 4.7a
Basic Shapes
 Bacillus (rod-shaped)
 Coccus (spherical)
 Spiral
 Spirillum
 Vibrio
 Spirochete
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Figures 4.1a, 4.2a, 4.2d, 4.4a, 4.4b, 4.4c
Bacillus or Bacillus
 Scientific name: Bacillus
 Shape: Bacillus
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Figure 4.3
Unusually Shaped Bacteria
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Figure 4.5a
Unusually Shaped Bacteria
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Figure 4.5b
Arrangements
 Pairs: Diplococci,
diplobacilli
 Clusters:
Staphylococci
 Chains:
Streptococci,
streptobacilli
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Figures 4.1a, 4.1d, 4.2b, 4.2c
Check Your Understanding
Check Your Understanding
 How would you be able to identify streptococci
through a microscope? 4-2
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The Structure of a Prokaryotic Cell
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Figure 4.6
Structures External to the Cell Wall
Learning Objectives
4-3 Describe the structure and function of the
glycocalyx.
4-4 Differentiate flagella, axial filaments, fimbriae, and
pili.
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Glycocalyx
 Outside cell wall
 Usually sticky
 Capsule: neatly
organized
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 Slime layer: unorganized
and loose
 Extracellular
polysaccharide allows
cell to attach
 Capsules prevent
phagocytosis
Figure 24.12
Flagella
 Outside cell wall
 Made of chains of
flagellin
 Attached to a protein
hook
 Anchored to the wall
and membrane by the
basal body
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Figure 4.8b
The Structure of a Prokaryotic
Flagellum
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Figure 4.8a
Arrangements of Bacterial Flagella
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Figure 4.7
Motile Cells
 Rotate flagella to run or tumble
 Move toward or away from stimuli (taxis)
 Flagella proteins are H antigens
(e.g., E. coli O157:H7)
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Motile Cells
ANIMATION Motility
ANIMATION Flagella: Structure
ANIMATION Flagella: Movement
ANIMATION Flagella: Arrangement
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Figure 4.9a
Axial Filaments
 Also called endoflagella
 In spirochetes
 Anchored at one end
of a cell
 Rotation causes cell
to move
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Figure 4.10a
A Diagram of Axial Filaments
ANIMATION Spirochetes
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Figure 4.10b
Fimbriae and Pili
 Fimbriae allow attachment
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Figure 4.11
Fimbriae and Pili
 Pili
 Facilitate transfer of DNA from one cell to another
 Gliding motility
 Twitching motility
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Check Your Understanding
Check Your Understanding
 Why are bacterial capsules medically important? 4-3
 How do bacteria move? 4-4
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The Cell Wall
Learning Objectives
4-5 Compare and contrast the cell walls of grampositive bacteria, gram-negative bacteria, acidfast bacteria, archaea, and mycoplasmas.
4-6 Compare and contrast archaea and
mycoplasmas.
4-7 Differentiate protoplast, spheroplast, and L form.
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The Cell Wall
 Prevents osmotic lysis
 Made of peptidoglycan (in bacteria)
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Figure 4.6
Peptidoglycan
 Polymer of
disaccharide:
 N-acetylglucosamine
(NAG)
 N-acetylmuramic acid
(NAM)
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Figure 4.12
Peptidoglycan in Gram-Positive
Bacteria
 Linked by polypeptides
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Figure 4.13a
Gram-Positive Bacterial Cell Wall
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Figure 4.13b
Gram-Negative Bacterial Cell Wall
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Figure 4.13c
Gram-positive
Cell Wall
Gram-positive
Cell Wall
 Thick peptidoglycan
 Teichoic acids
 Thin peptidoglycan
 Outer membrane
 Periplasmic space
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Figure 4.13b–c
Gram-Positive Cell Walls
 Teichoic acids
 Lipoteichoic acid links to plasma membrane
 Wall teichoic acid links to peptidoglycan
 May regulate movement of cations
 Polysaccharides provide antigenic variation
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Figure 4.13b
Gram-Negative Cell Wall
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Figure 4.13c
Gram-Negative Outer Membrane
 Lipopolysaccharides, lipoproteins, phospholipids
 Forms the periplasm between the outer membrane
and the plasma membrane
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Figure 4.13c
Gram-Negative Outer Membrane
 Protection from phagocytes, complement, and
antibiotics
 O polysaccharide antigen, e.g., E. coli O157:H7
 Lipid A is an endotoxin
 Porins (proteins) form channels through membrane
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The Gram Stain
(a) Gram-Positive
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(b) Gram-Negative
Table 4.1
The Gram Stain Mechanism
 Crystal violet-iodine crystals form in cell
 Gram-positive
 Alcohol dehydrates peptidoglycan
 CV-I crystals do not leave
 Gram-negative
 Alcohol dissolves outer membrane and leaves holes in
peptidoglycan
 CV-I washes out
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Gram-Positive
Cell Wall
Gram-Negative
Cell Wall
 2-ring basal body
 Disrupted by lysozyme
 Penicillin sensitive
 4-ring basal body
 Endotoxin
 Tetracycline sensitive
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Figure 4.13b–c
Atypical Cell Walls
 Acid-fast cell walls




Like gram-positive
Waxy lipid (mycolic acid) bound to peptidoglycan
Mycobacterium
Nocardia
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Figure 24.8
Atypical Cell Walls
 Mycoplasmas
 Lack cell walls
 Sterols in plasma membrane
 Archaea
 Wall-less or
 Walls of pseudomurein (lack NAM and D-amino acids)
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Damage to the Cell Wall




Lysozyme digests disaccharide in peptidoglycan
Penicillin inhibits peptide bridges in peptidoglycan
Protoplast is a wall-less cell
Spheroplast is a wall-less gram-positive cell
 Protoplasts and spheroplasts are susceptible to osmotic
lysis
 L forms are wall-less cells that swell into irregular
shapes
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Check Your Understanding
Check Your Understanding
 Why are drugs that target cell wall synthesis useful?
4-5
 Why are mycoplasmas resistant to antibiotics that
interfere with cell wall synthesis? 4-6
 How do protoplasts differ from L forms? 4-7
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Structures Internal to the Cell Wall
Learning Objectives
4-8 Describe the structure, chemistry, and functions
of the prokaryotic plasma membrane.
4-9 Define simple diffusion, facilitated diffusion,
osmosis, active transport, and group
translocation.
4-10 Identify the functions of the nucleoid and
ribosomes.
4-11 Identify the functions of four inclusions.
4-12 Describe the functions of endospores,
sporulation, and endospore germination.
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The Plasma Membrane
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Figure 4.14a
The Plasma Membrane





Phospholipid bilayer
Peripheral proteins
Integral proteins
Transmembrane
Proteins
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Figure 4.14b
Fluid Mosaic Model
 Membrane is as viscous as olive oil
 Proteins move to function
 Phospholipids rotate
and move laterally
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Figure 4.14b
The Plasma Membrane
 Selective permeability allows passage of some
molecules
 Enzymes for ATP production
 Photosynthetic pigments on foldings called
chromatophores or thylakoids
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Chromatophores
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Figure 4.15
The Plasma Membrane
 Damage to the membrane by alcohols, quaternary
ammonium (detergents), and polymyxin antibiotics
causes leakage of cell contents
ANIMATION Membrane Structure
ANIMATION Membrane Permeability
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Movement of Materials across
Membranes
 Simple diffusion:
Movement of a solute
from an area of high
concentration to an
area of low
concentration
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Figure 4.17a
Movement of Materials across
Membranes
 Facilitated diffusion: Solute combines with a
transporter protein in the membrane
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Figure 4.17b-c
Movement of Materials across
Membranes
ANIMATION Passive Transport: Special Types of Diffusion
ANIMATION Passive Transport: Principles of Diffusion
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Movement of Materials across
Membranes
 Osmosis: The
movement of water
across a selectively
permeable membrane
from an area of high
water to an area of
lower water
concentration
 Osmotic pressure: The
pressure needed to stop
the movement of water
across the membrane
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Figure 4.18a
Movement of Materials across
Membranes
 Through lipid layer
 Aquaporins (water
channels)
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Figure 4.17d
The Principle of Osmosis
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Figure 4.18a–b
The Principle of Osmosis
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Figure 4.18c–e
Movement of Materials across
Membranes
 Active transport: Requires a transporter protein
and ATP
 Group translocation: Requires a transporter protein
and PEP
ANIMATION Active Transport: Types
ANIMATION Active Transport: Overview
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Check Your Understanding
Check Your Understanding
 Which agents can cause injury to the bacterial
plasma membrane? 4-8
 How are simple diffusion and facilitated diffusion
similar? How are they different? 4-9
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Cytoplasm
 The substance inside the plasma membrane
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Figure 4.6
The Nucleoid
 Bacterial chromosome
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Figure 4.6
Ribosomes
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Figure 4.6
The Prokaryotic Ribosome
 Protein synthesis
 70S
 50S + 30S subunits
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Figure 4.19
Magnetosomes
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Figure 4.20
Inclusions
 Metachromatic granules
(volutin)
 Polysaccharide granules
 Lipid inclusions
 Sulfur granules
 Carboxysomes
 Gas vacuoles
 Magnetosomes
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 Phosphate reserves




Energy reserves
Energy reserves
Energy reserves
Ribulose 1,5-diphosphate
carboxylase for CO2 fixation
 Protein-covered cylinders
 Iron oxide
(destroys H2O2)
Endospores





Resting cells
Resistant to desiccation, heat, chemicals
Bacillus, Clostridium
Sporulation: Endospore formation
Germination: Return to vegetative state
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Endospores
Figure 4.21b
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Formation of Endospores by
Sporulation
Figure 4.21a
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Check Your Understanding
Check Your Understanding
 Where is the DNA located in a prokaryotic cell? 4-10
 What is the general function of inclusions? 4-11
 Under what conditions do endospores form? 4-12
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The Eukaryotic Cell
Figure 4.22a
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Flagella and Cilia
Learning Objective
4-13 Differentiate prokaryotic and eukaryotic flagella.
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Flagella and Cilia
Figure 4.23a-b
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Flagella and Cilia
 Microtubules
 Tubulin
 9 pairs + 2 array
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Figure 4.23c
The Cell Wall and Glycocalyx
Learning Objective
4-14 Compare and contrast prokaryotic and eukaryotic
cell walls and glycocalyxes.
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The Cell Wall and Glycocalyx
 Cell wall
 Plants, algae, fungi
 Carbohydrates
 Cellulose, chitin, glucan, mannan
 Glycocalyx
 Carbohydrates extending from animal plasma membrane
 Bonded to proteins and lipids in membrane
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Q&A
 Penicillin was called a
“miracle drug” because
it doesn’t harm human
cells. Why doesn’t it?
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The Plasma Membrane
Learning Objective
4-15 Compare and contrast prokaryotic and eukaryotic
plasma membranes.
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The Plasma Membrane






Phospholipid bilayer
Peripheral proteins
Integral proteins
Transmembrane proteins
Sterols
Glycocalyx carbohydrates
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The Plasma Membrane
 Selective permeability allows passage of some
molecules
 Simple diffusion
 Facilitative diffusion
 Osmosis
 Active transport
 Endocytosis
 Phagocytosis: Pseudopods extend and engulf particles
 Pinocytosis: Membrane folds inward, bringing in fluid and
dissolved substances
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Cytoplasm
Learning Objective
4-16 Compare and contrast prokaryotic and eukaryotic
cytoplasms.
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Cytoplasm
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Table 4.2
Cytoplasm
 Cytoplasm membrane: Substance inside plasma
and outside nucleus
 Cytosol: Fluid portion of cytoplasm
 Cytoskeleton: Microfilaments, intermediate
filaments, microtubules
 Cytoplasmic streaming: Movement of cytoplasm
throughout cells
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Ribosomes
Learning Objective
4-17 Compare the structure and function of eukaryotic
and prokaryotic ribosomes.
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Ribosomes
 Protein synthesis
 80S
 Membrane-bound: Attached to ER
 Free: In cytoplasm
 70S
 In chloroplasts and mitochondria
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Check Your Understanding
Check Your Understanding
 Identify at least one significant difference between
eukaryotic and prokaryotic flagella and cilia, cell
walls, plasma membranes, and cytoplasm.
4-13–4-16
 The antibiotic erythromycin binds with the 50S
portion of a ribosome. What effect does this have on
a prokaryotic cell? On a eukaryotic cell? 4-17
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Organelles
4-18 Define organelle.
4-19 Describe the functions of the nucleus,
endoplasmic reticulum, Golgi complex,
lysosomes, vacuoles, mitochondria, chloroplasts,
peroxisomes, and centrosomes.
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Organelles





Nucleus: Contains chromosomes
ER: Transport network
Golgi complex: Membrane formation and secretion
Lysosome: Digestive enzymes
Vacuole: Brings food into cells and provides support
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Organelles




Mitochondrion: Cellular respiration
Chloroplast: Photosynthesis
Peroxisome: Oxidation of fatty acids; destroys H2O2
Centrosome: Consists of protein fibers and
centrioles
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The Eukaryotic Nucleus
Figure 4.24
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The Eukaryotic Nucleus
Figure 4.24a–b
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Rough Endoplasmic Reticulum
Figure 4.25
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Detailed Drawing of Endoplasmic
Reticulum
Figure 4.25a
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Micrograph of Endoplasmic Reticulum
Figure 4.25b
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Golgi Complex
Figure 4.26
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Lysosomes and Vacuoles
Figure 4.22b
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Mitochondria
Figure 4.27
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Chloroplasts
Figure 4.28
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Chloroplasts
Figure 4.28a
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Chloroplasts
Figure 4.28b
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Peroxisome and Centrosome
Figure 4.22b
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Check Your Understanding
Check Your Understanding
 Compare the structure of the nucleus of a eukaryote
and the nucleoid of a prokaryote. 4-18
 How do rough and smooth ER compare structurally
and functionally? 4-19
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The Evolution of Eukaryotes
Learning Objective
4-20 Discuss evidence that supports the
endosymbiotic theory of eukaryotic evolution.
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Endosymbiotic Theory
Figure 10.2
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Endosymbiotic Theory
 What are the fine extensions on this protozoan?
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Endosymbiotic Theory
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Check Your Understanding
Check Your Understanding
 Which three organelles are not associated with the
Golgi complex? What does this suggest about their
origin? 4-20
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